-- Discussion containing changed information from previous version are highlighted. --
644
FXUS64 KMRX 040536
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
136 AM EDT Tue Jun 4 2024

...New AVIATION...

.UPDATE...
Issued at 919 PM EDT Mon Jun 3 2024

A few isolated showers and thunderstorms have developed across the
region this evening, and while a general decrease in coverage is
expected overnight, there`s still a small (10% chance) of isolated
convection overnight with sufficient low-level moisture, subtle
upper level shortwaves, and residual outflow boundaries. More
widespread convection is expected on Tuesday afternoon with
scattered showers and thunderstorms expected.

JB

&&

.SHORT TERM...
(This evening through Tuesday)...
Issued at 325 PM EDT Mon Jun 3 2024

Key Messages:

1. Most areas have stayed dry today with only a few isolated
showers and thunderstorms around this afternoon. These storms have
been across southeast Tennessee, southwest North Carolina and the
northern Cumberland Plateau.

2. Tonight there will be some patchy fog, locally dense in places
with only a few showers lingering into th evening.

3. Increasing rain chances Tuesday with more widespread coverage,
especially during the afternoon hours.

Discussion:

More sunshine, with warmer afternoon temperatures today. Some
isolated showers and storms were moving across the Cumberland
Plateau and southeast TN and southwest NC this afternoon. This
convection should weaken early this evening. Some patchy fog will
form as winds will be light and low level moisture is high. Weak
ridging is still over the eastern Tennessee Valley both at the
surface and aloft. A shortwave trough moving into the lower MS
Valley tonight will set off storms to the west and then they will
move into west TN, MS and AL overnight tonight and early Tuesday.
Outflows from any thunderstorm complexes will be the focus for
more development farther east Tuesday and shift east or northeast
through the forecast area Tuesday afternoon. This will usher in
another wet pattern the next couple days. Lowered rainfall amounts
from what was originally in the grids for tomorrow afternoon. But
some heavier showers could produce significant rainfall locally.

Per SPC Day 2 outlook afternoon thunderstorms are possible as one
or more convectively enhanced vorticity maxima float across the
Ozarks into the TN Valley region. A seasonally moist and
moderately unstable, but weakly sheared environment is forecast.
Some local enhancement to shear is possible near remnant MCVs or
outflow boundaries moving through the area. Isolated strong to
severe storms capable of strong gusts and marginal hail will be
possible through early evening. This area will be mainly west of
the forecast area but some strong storms could affect the southern
plateau later in the day.


&&

.LONG TERM...
(Tuesday night through next Monday)...
Issued at 325 PM EDT Mon Jun 3 2024

Key Message:

Multiple rounds of showers and storms are expected Tuesday into
Thursday. A few strong to marginally severe storms cannot be ruled
out Wednesday, with damaging winds the primary threat. Isolated
flash flooding is also possible.

Discussion:

By Tuesday night the shortwave will be lifting out towards the
northeastern United States, and helping to act as the focal point of
the first round of thunderstorms. We should see a uptick in storm
strength and coverage during the afternoon hours on Tuesday
coinciding with peak heating. Wednesday looks to be the greatest
chance to see the strongest thunderstorms of the week as the jet
aloft helps to amplify lift and the LLJ increases in strength as the
front approaches the area. Forecast soundings show that there is
enough instability to support healthy thunderstorm development, and
with the increasing LLJ shear gets an uptick to around 20-30 knots,
which would help storms maintain strength. With the drier air aloft
the DCAPe values also jump up over 500 J/kg, which suggests
collapsing thunderstorms could have enough momentum behind them to
cause sporadic wind damage. At this time am not expecting widespread
severe thunderstorms, but some of the strongest storms of the day
could briefly see severe level winds... In addition the higher PWAT
values of around 1.75" will help to produce heavy downpours under
the core of these storms, and an isolated flooding risk.

Thursday should see some additional shower activity as the front
moves through, but QPF and storm coverage should both be lower than
Wednesday. We should see a break in activity heading into the
weekend as the low continues to swing around the New England region,
and drier northwest air flows into the region. Temperatures through
the weekend should be fairly mild with most locations topping out
around the 80 degree mark.

&&

.AVIATION...
-- Changed Discussion --
(06Z TAFS)
Issued at 132 AM EDT Tue Jun 4 2024

TRI still looks to have best chance for fog impacts this morning
as high clouds continue to stream in from the west. Will
definitely need to monitor obs around TYS as they will be on the
edge of these clouds, and have a more uncertain potential for
fog as a result. Showers and thunderstorm will move west to east
across the area tomorrow afternoon and through the evening hours.
Reduced vis and cigs possible with any heavier downpours but
predominant MVFR conditions are not expected at this time.
-- End Changed Discussion --

&&

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --
Chattanooga Airport, TN             84  69  86  69 /  70  40  80  60
Knoxville McGhee Tyson Airport, TN  84  67  83  68 /  70  50  90  80
Oak Ridge, TN                       83  66  82  66 /  70  60  90  70
Tri Cities Airport, TN              84  63  81  66 /  60  40  90  80
-- End Changed Discussion --

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

$$

SHORT TERM...TD
AVIATION...KRS